1. Field of the Invention
The present invention relates to a line-sequential driving display and, in particular, relates to a technique for increasing the contrast of the display.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2000-228151 discloses a technique of forming a mask layer having an optical constant, varied depending on either short-wavelength light or heat caused by discharge, on a front substrate in order to prevent a reduction in contrast due to external light. Specifically, a front substrate including the mask layer has a low transmittance while a panel does not emit light. When the panel emits light, the transmittance of the front substrate including the mask layer increases. This leads to a reduced amount of reflected external light in a portion where light is not emitted, thus effectively radiating light emitted from phosphor, as disclosed in Japanese Patent Laid-Open No. 2000-228151.
Japanese Patent Laid-Open No. 10-106450 discloses a technique of partially suppressing the reflection of external light components having various wavelengths using optical filter layers and transmitting internally emitted light (internal light) through the filter layers to efficiently transmit the internal light and block the external light using the dependence of the transmittance of each filter on wavelength.
Since phosphor has long-persistence and degradation characteristics peculiar to such a material, it is necessary to perform time control of a light transmitting state and a light blocking state of a light blocking layer in accordance with a change in the characteristics. According to the technique disclosed in Japanese Patent Laid-Open No. 10-106450, although the contrast is increased, pixels reflect external light at any time during turn-off. It is therefore difficult to remarkably increase the contrast.